Color cathode ray tube

Abstract

A phosphor screen comprising three color phosphor layers that emit red, green, and blue light is provided on the inner surface of a panel of an envelope, and an in-line type electron gun assembly for emitting three electron beams aligned on the same axis (generally a horizontal axis X) is mounted in a neck. This electron gun assembly has three cathodes arranged in a row, and a plurality of electrodes for sequentially focusing and accelerating the electron beams from the respective cathodes toward the phosphor screen. A pair of belt-like magnetic segments are provided on the outer wall of the neck of the envelope to serve as magnetic members for adjusting an external magnetic field. Each magnetic segment is made of a hot-rolled silicon steel plate having a thickness of 0.35 mm, a width of 4 mm, and a length of 40 mm in the direction of the tube axis. The magnetic segments are arranged such that their centers in the longitudinal direction correspond to the cathodes on an electron beam alignment plane, and extend in the back-and-forth direction of the tube axis each by 20 mm about the cathodes as the center. By these magnetic segments, a change in convergence caused by the external magnetic field can be suppressed.